1. Field of the Invention
This invention relates to the field of containers, especially for consumer products, and in particular to a bottle for viscous substances having an internal contour adapted to accumulate the viscous substance at a lowermost point in the container when upright, and a supplemental opening with a removable closure at the lowermost point for removing the accumulated viscous substance under gravity feed.
2. Prior Art
Typical containers for consumer products hav substantially-flat inside bottom contours or domed bottom contours. When such containers are nearly empty, the contents of the container are spread more or less evenly around the circumference and over a relatively large area. Surface tension and wetting effects cause a quantity of the material, especially viscous liquid material such as shampoo, to cling to the bottom of the container. Material also clings to the side walls when the container is tilted upside down in attempts to extract the contents. Frequently, users of shampoo, thick food products such as salad dressing, sauces, ketchup and similar viscous materials store the containers upside down in order to cause the viscous material to accumulate at the primary closure on the primary opening at the top of the neck of the container, e.g. bottle. Usually, the closure is a threaded cap. While such a technique is effective at extracting the contents of containers, and will allow the user to use the "last drop" of contents, the procedure is cumbersome.
Some containers for liquid products have irregular bottom contours. U.S. Pat. No. Des. 225,975 - Danjczek discloses a bottle for use as an ink well, including means defining a narrowing cross section terminating at the bottom surface along a line. The last portion of ink or the like is confined along the line at the bottom and can be extracted. The bottom forms a trough defined by the inner bottom walls. The material of course also can be extracted through the primary opening.
Users who desire to accumulate material in a container at a relatively confined bottom area could also employ the container of U.S. Pat. No. Des. 175,196 - Suttle. This container has a flattened side upon which the container can be rested while tilted, to thereby accumulate material at the edge of the bottom. This is effective to accumulate viscous material in a relatively smaller area and will presumably allow the user to extract a greater proportion of the material by avoiding undue wetting across a wide, flat bottom surface. However, the material still must be extracted through the primary opening and wetting of the material along the sides of the bottle as the material flows to the primary opening will make it impossible to promptly extract most or all of the material. According to known disclosures, wetting of the sides of the container is unavoidable when tilting the container, and the contents cannot be completely extracted.
Not all containers are flat on the inner walls of their bottoms. U.S. Pat. No. Des. 25,056 shows a bottle in which the inner contour of the bottom is domed. When this container is nearly empty, the contents will accumulate in an annular area near the side walls. Similarly, U.S. Pat. No. 4,121,103 - Calhoun, in connection with means for detecting residual contents in containers shows as alternatives both a domed container and a container with a sloping bottom. In connection with the domed bottom residual material accumulates in an annular configuration. In the sloping bottom the material accumulates at one side. Neither of these patents teaches a supplemental opening with removable closure at the lowermost point, that can be opened by the user when the contents of the container are nearly gone. Therefore the user is unable to extract the last portion of the contents because by tilting the bottle to cause material to flow to the neck of the container, and thereby allowing wetting of the sides of the bottle, complete removal of the material is precluded.
Some containers such as cans for cooking oil or fuels, container drums and other large volume containers often have supplemental openings for admitting air to the container to speed draining. These supplemental openings are typically located at an uppermost point in the container or at an upper point when the container is tilted for pouring.
According to the invention, a bottle particularly of the type used for viscous consumer products is provided with a supplemental opening with a removable closure at the bottom in the form of a plug a tethered plug or a frangible panel. The supplemental opening is disposed at a lowermost point in the container, for example at the bottom of a slope along the bottom. The inner surface of the bottom, i.e., the surface defining the bottom of the storage volume, forms a flat or curving slope leading to the supplemental opening. As the contents of the material are exhausted, the last bit of material accumulates directly over the supplemental opening. When extracting the last portion of the contents, wetting of the inner surface occurs only immediately adjacent the supplemental opening, and not over a large area of a material flow path leading from the bottom of the container along the sidewalls to the primary closure. The bottom can be configured in a flat sloping, multiple-surface-slanted or roundly-slanted configuration. The supplemental opening can be placed along the lowermost bottom edge at a sidewall or in the bottom. The bottom can be of varying thickness defining an incline leading to the supplemental opening or of uniform thickness, the bottom wall being disposed at a tilt toward the supplemental opening.